os.walk() in Python

os.walk() in Python is used to traverse directories recursively, allowing you to access all files and subdirectories in a directory tree. It is particularly useful when you need to perform operations on files spread across multiple folders.

Example: This code demonstrates how to traverse the current directory and print all directories and files.

import os

for root, dirs, files in os.walk('.'):
    print("Current directory:", root)
    print("Subdirectories:", dirs)
    print("Files:", files)
    print('----------------')

Current directory: .
Subdirectories: []
Files: ['Solution.py', 'input.txt', 'output.txt', 'driver']
----------------

Explanation:

• os.walk('.') generates a tuple (root, dirs, files) for each directory.
• root gives the current directory path.
• dirs lists all subdirectories in root.
• files lists all files in root.

Syntax:

os.walk(top, topdown=True, onerror=None, followlinks=False)

Parameters:

• top: The root directory path to start traversal.
• topdown: Boolean (default True). If True, directories are traversed top-down, else bottom-up.
• onerror: Function called with an OSError instance if an error occurs.
• followlinks: Boolean (default False). If True, symbolic links to directories are followed.

Examples

Example 1: This program finds all .txt files in the directory tree.

import os
a = [f for r, d, files in os.walk('.') for f in files if f.endswith('.txt')]
print("Text files:", a)

Text files: ['input.txt', 'output.txt']

Explanation: f.endswith('.txt') filters files ending with .txt using files.

Example 2: This code counts the total number of files recursively in the given directory.

import os
res = sum(len(files) for r, d, files in os.walk('.'))
print("Total files:", res)

Total files: 4

Explanation:

• len(files) counts files in each folder.
• sum(...) accumulates counts from all directories.

Example 3: This program prints all directory paths in the directory tree.

import os
res = [r for r, d, files in os.walk('.')]
print("Directories:", res)

Directories: ['.']

Explanation:

• r gives the current directory path.
• List comprehension collects all directories into dirs_list.